Printing silk with chrome dyestuffs



Patented Jan. 9, 1934 UNITED STATES 1,942,774 PRINTING SILK WITH CHROMEnrnsrnrrs Jean-Jacques Roulet, Basel, Switzerland, assignor to firm:Durand & Huguenin .S. A., Basel,

Switzerland No Drawing. Application October 10, 1932, Serial No.637,213, and in Germany October 22,

4 Claims.

Chrome dyestuffs have been used inprinting silk only to a limitedextent, owing to. the fact that gum thickening, which otherwise is themost suitable for silk, cannot be used, because 5 in presence ofchromium salts, for instance chromium acetate, coagulation occurs duringthe steaming and the printed parts become harsh. Subsequent rinsing orsoaping does not remove this drawback, the silk retains a harsh feeland, besides, the printed parts lose their lustre. In such cases one istherefore compelled to use British gum or dextrin as the thickening,which, it is true, does not involve said drawback, but gives less fulland less sharp prints. If the chrome dyestuffs are printed with the aidof gum but without a chrome mordant, prints are obtained which are notof harsh feel, but, as it is well known, this mode of operating yieldsshades which are lacking in fastness.

It has now been found that chrome dyestuffs can be printed on naturalsilk; even when gum thickening is used, without encountering the abovementioned drawbacks, like harsh feel or loss of lustre, if there. beadded to the printing paste a soluble sulphocyanide, an aliphaticpolyalcohol or a substitution product thereof, such as glycerine,glycol, monoethylglycol or acetyl' glycerine, and also a body of theurea-group,

- such as the urea, thio-urea, guanidine. In this manner there areobtained on natural silk intense, vivid prints of soft feel and of a.fastness considerably enhanced as compared with those obtained when nochrome mordant is used. The invention is illustrated by the followingexamples, the parts being by weight:

Examples Nos. 1-6

Chromocitronine R .(Color Index No. 441) Ohromocitronino 3R (similar tosaid No. 441) 3 Disazo-dyestufi from paraphenylenc-diaminesulphonic acidand 2 mol. salicyclie acid (see U.S. Patent No. 1,815,827, Ex-

ample 2) 'lrisazddyestnfi, obtained from alkaline oxidation of4-amino-2-sulphobenzeneazosalicyclic acid (see En rrlishSpecification-No. 349,-

. 609, Example 1) Chromorhodine B (Color Index 762) Chromazurine D Index879) Parts Urea 'Ammonium sulphocyanide Gum thickening (1:1) Solution ofchromium acetate (20 Be) q 'OUNDOJM es ovuouwmm The ,dyestufi is madeinto a paste with water, the glycerine, the urea and the ammoniumsulphocyanide, then the thickening is added and the whole is heated uponwater-bath until complete dissolution occurs. After cooling down thechrome mordant is added.

Silk is printed with this printing colour, dried, steamed'for 1 hourunder light steam pressure (0.2-0.3 atm.), rinsed in cold water andfinally washed carefully in tepid water at 40 C. The final washing watermust be nearly colourless. There is obtained a yellow, golden yellow,orange, red-brown, red, blue, respectively, fast print on the naturalsilk of faultless feel.

Examples Nos. 7-10 Ammonium sulphocyan Gum thickening (1:1) 68 Solutionof chromium acetate of 20 Be-" 9 The dyestuff is made Pinto a paste withthe organic acid, if necessary lwith addition of hydrosulphite solution.Then the glycerine, urea, ammonium sulphocyanide and the thickening areadded, and the whole is heated up until dissolution is complete. Aftercooling down the chrome mordant is added.

The goods are printed with this printing colour,

dried and steamed at a steam-pressure of 0.2-0.3 0

atm. They are then thoroughly washed, first in cold and afterwards inlukewarm water.

In this manner fast blue, marine blue and violet prints are obtained onnatural silk. The printed places have the same soft feel as the 5unprinted parts.

In these examples, similar results are obtained if urea is replaced byanother body of the ureagroup, such as thio-urea, guanidine or the like.

The ammonium sulphocyanide can be replaced by another solublesulphocyanide, such as that of potassium, sodium or calcium. Also theglycerine can be replaced by another aliphatic polyalcohol, such asglycol, thiodiethyleneglycol, diethyleneglycol or a substitution productthereof, 5

such as acetylglycerine, monoethylglycol, di-

ethyleneglycolmonoor di-ethylether. In each case fast prints of goodsoft feel are obtained.

What I claim is;-

1. A process for printing natural silk with chrome dyestuffs, with theaid of gum thickening and a chrome mordant, said process producing vividprints of soft feel and of good fastness and consisting in incorporatingin a printing paste a watersoluble salt of hydrosulphocyanic acid, analiphatic polyalcohol and a body of the urea group and then printing thepaste thus prepared on the fabric, whereupon the usual furtheroperations for the purpose specified may follow.

2. A process for printing natural silk with chrome dyestuffs, with theaid of gum thickening and a chrome mordant, said process producing vividprints of soft feel and of good fastness and consisting in incorporatingin a printing paste sulphocyanide of ammonium, an aliphatic polyalcoholand a body of the urea group, and then printing the paste thus preparedon the fabric, whereupon the usual further operations for the purposespecified may follow.

3. A process for printing natural silk with chrome dyestuffs, with theaid of gum thickening and a chrome mordant; said process producing vividprints of soft feel and of good fastness and consisting in incorporatingin a printing paste a 'watersoluble salt of hydrosulphocyanic acid,glycerine and a body of the urea group and then printing the paste thusprepared on the fabric, whereupon the usual further operations for thepurpose specified may follow. I

4. A process for printing natural silk with chrome dyestuffs, with theaid of gum thickening and a chrome mordant, said process producing vividprints of soft feel and of good fastness and consisting in incorporatingin a printing paste a watersoluble salt of -hydrosulphocyanic acid, analiphatic polyalcohol and urea and then printing the paste thus preparedon the fabric, whereupon the usual further operations for the purposespecified may follow.

JEAN-JACQUES ROULET,

